<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>03_边框与内间距测试</title>
    <style>
        .di {
            width: 200px;
            height: 200px;
            background-color: #0aa1ed;
            border-top: 10px solid #f0f;
            border: 5px solid #f00;
            /*边框圆角：值越大 角越圆 值为正方形宽高的一半可以切圆*/
            border-radius: 100px;
        }
        .d2 {
            width: 200px;
            height: 60px;
            background-color: cyan;
            border-radius: 30px;

        }
        .d4 {
            width: 200px;
            height: 200px;
            background-color: cyan;
            border: 10px solid #00f;
            padding-left: 50px;
            margin: 50px;
        /*    盒子模型计算方案切换为边框盒子
        无论是假内间距还是边框，元素的大小都不会改变*/
            box-sizing: border-box;
        }
        span {
            background-color: #ff0;
        }
        .s2 {
            padding: 50px;
        }
    </style>
</head>
<body>
    <div class="di"></div>
    <div class="d2"></div>
    <div class="d4">内间距测试</div>
<span>span1</span><span class="s2">span2</span><span>span3</span>
<h1>我是标题哈哈哈哈哈哈哈哈</h1>
</body>
</html>